Exploration doesn't pay much when compared to top earning methods, but as it is now, it pays a lot when compared to how few credits you have to invest in it to reach maximum income. Basically, you need to buy a DSS module for 250,000 Cr, and that's it. Of course, there are optional stuff like fuel scoops, but you could set up a Sidewinder for something like 1-2 million credits that would do it all. Meaning if you scanned and mapped two already-tagged ELWs, you're all set.
Meanwhile, a Sidewinder wouldn't get you anywhere near the top earning methods for combat, trade, mining etc. So, exploration, and now exobiology as well, have a very low barrier to entry, and you hit the ceiling of credits per hour nearly instantly.
If memory serves, exploration would do around 15 million Cr per hour at most (without a LYR bonus), so with the Odyssey mapping bonus, I suppose it would be around 20 MCr/h. I could recalculate it and see if this still holds true, but what for? That's obviously not going to reach the highest(!) income rates of other professions, and that's in my opinion fine.